Moving picture coding method, moving picture decoding method, moving picture coding apparatus, moving picture decoding apparatus, and moving picture coding and decoding apparatus

ABSTRACT

A moving picture coding method includes (i) transforming, for each of one or more second processing units included in the first processing unit, a moving picture signal in a spatial domain into a frequency domain coefficient and quantizing the frequency domain coefficient, and (ii) performing arithmetic coding on a luminance CBF flag indicating whether or not a quantized coefficient is included in the second processing unit in which transform and quantization are performed, wherein, in the arithmetic coding, a probability table for use in arithmetic coding is determined according to whether or not the size of the first processing unit is identical to the size of the second processing unit and whether or not the second processing unit has a predetermined maximum size.

TECHNICAL FIELD

One or more exemplary embodiments disclosed herein relate generally to amoving picture coding method and a moving picture coding apparatus whichcode a flag which indicates whether or not there is a transformcoefficient of a coding target block such that an image is coded foreach of the blocks, and a moving picture decoding method, a movingpicture decoding apparatus, and a moving picture coding and decodingapparatus which decode a flag which indicates whether or not there is acoded transform coefficient.

BACKGROUND ART

In recent years, there have been an increasing number of applicationsfor video-on-demand type services, for example, including videoconferences, digital video broadcasting, and streaming of video contentvia the Internet, and these applications depend on transmission of videoinformation. At the time of transmission or recording of video data, aconsiderable amount of data is transmitted through a conventionaltransmission path of a limited bandwidth or is stored in a conventionalrecording medium with limited data capacity. In order to transmit videoinformation through a conventional transmission channel and store videoinformation in a conventional recording medium, it is essential tocompress or reduce the amount of digital data.

Thus, a plurality of video coding standards have been developed forcompressing video data. Such video coding standards include, forexample, International Telecommunication Union TelecommunicationStandardization Sector (ITU-T) standards denoted as H.26x, and theISO/IEC standards denoted as MPEG-x. The most up-to-date and advancedvideo coding standard is currently the standard denoted as H.264/AVC orMPEG-4/AVC (refer to Non Patent Literature 1).

The coding approach which serves as a basis for these standards is basedon prediction coding including major steps to be shown the following (a)to (d). a) In order to perform data compression on a block level foreach of the video frames, the video frame is divided into blocks ofpixel. (b) By predicting each of the blocks from the already coded videodata, temporal and spatial redundancy is specified. (c) By subtractingthe prediction data from the video data, the specified redundancy iseliminated. (d) By Fourier transform, quantization, and entropy coding,the remaining data (residual blocks) are compressed.

CITATION LIST Non Patent Literature

[NPL 1]

ITU-T Recommendation H.264 “Advanced video coding for genericaudiovisual services,” March 2010

[NPL 2]

JCT-VC “WD3: Working Draft 3 of High-Efficiency Video Coding,”JCTVC-E603, March 2011

SUMMARY OF INVENTION Technical Problem

Recently, there has been a growing need for a further increase in codingefficiency against the backdrop of progress in high-definition movingpictures.

Therefore, the present disclosure has an object to provide a movingpicture coding method, a moving picture coding apparatus, a movingpicture decoding method, a moving picture decoding apparatus, and amoving picture coding and decoding apparatus which have high codingefficiency.

Solution to Problem

A moving picture coding method according to one non-limiting andexemplary embodiment is a method for coding a moving picture signal foreach of the first processing units. More specifically, the movingpicture coding method comprising: transforming, for each of one or moresecond processing units included in the first processing unit, themoving picture signal in a spatial domain into a frequency domaincoefficient and quantizing the frequency domain coefficient; andperforming arithmetic coding on a luminance CBF flag indicating whetheror not a quantized coefficient is included in each of the secondprocessing units for which the transform and the quantization areperformed. In the performing of arithmetic coding, a probability tablefor use in the arithmetic coding is determined according to whether ornot a size of the first processing unit is identical to a size of thesecond processing unit and whether or not the second processing unit hasa predetermined maximum size.

It should be noted that the present disclosure can be realized orimplemented not only as coding methods and decoding methods, but alsoprograms for causing computers to execute each of the steps included inthe coding methods and decoding methods. Naturally, the programs can bedistributed through a non-transitory recording medium such as CompactDisc-Read Only Memories (CD-ROMs) and communication networks such as theInternet.

Advantageous Effects of Invention

The present disclosure makes it possible to efficiently performarithmetic coding and arithmetic decoding on a luminance CBF flag.

BRIEF DESCRIPTION OF DRAWINGS

These and other objects, advantages and features of the disclosure willbecome apparent from the following description thereof taken inconjunction with the accompanying drawings that illustrate a specificembodiment of the present disclosure. In the Drawings:

FIG. 1 is a block diagram showing a decoding apparatus including aluminance CBF flag decoding unit according to Embodiment 1;

FIG. 2 is a flowchart showing a flow of operations of a luminance CBFdecoding unit 101 according to the present disclosure;

FIG. 3 is a schematic view for explaining details of the luminance CBFdecoding unit 101 according to Embodiment 1;

FIG. 4 is a block diagram showing an example of a configuration of amoving image decoding apparatus according to Embodiment 1;

FIG. 5A is Table 1000 for use in arithmetic decoding according to thepresent embodiment and a table which corresponds to Table 0000 in FIG.28A;

FIG. 5B is Table 1001 for use in arithmetic decoding according to thepresent embodiment and a table which corresponds to Table 0001 in FIG.28B;

FIG. 5C is Table 1002 for use in arithmetic decoding according to thepresent embodiment and a table which corresponds to Table 0002 in FIG.28C;

FIG. 5D is Table 1003 for use in arithmetic decoding according to thepresent embodiment and a table which corresponds to Table 0003 in FIG.28D;

FIG. 6 is a diagram for explaining a method for obtaining ctxIdxIncwhich is a number for deriving a probability with respect to theluminance CBF flag according to Embodiment 1;

FIG. 7 is a flowchart showing a flow of operations of a luminance CBFflag coding unit according to Embodiment 2;

FIG. 8 is a block diagram showing an example of a configuration of animage coding apparatus according to Embodiment 2;

FIG. 9 is an overall configuration of a content providing system whichimplements content distribution services;

FIG. 10 is an overall configuration of a digital broadcasting system;

FIG. 11 is a block diagram showing an example of a configuration of atelevision;

FIG. 12 is a block diagram illustrating an example of a configuration ofan information reproducing/recording unit that reads and writesinformation from and on a recording medium that is an optical disk;

FIG. 13 is a diagram showing a configuration of a recording medium thatis an optical disk;

FIG. 14A is a diagram showing an example of a cellular phone;

FIG. 14B is a block diagram showing an example of a configuration of acellular phone;

FIG. 15 is a diagram showing a structure of multiplex data;

FIG. 16 is a diagram showing how to multiplex each stream in multiplexdata;

FIG. 17 is a diagram showing how a video stream is stored in a stream ofPES packets in more detail;

FIG. 18 is a diagram showing a structure of TS packets and sourcepackets in the multiplexed data;

FIG. 19 is a diagram showing a data structure of a PMT;

FIG. 20 is a diagram showing an internal structure of multiplexed datainformation;

FIG. 21 is a diagram showing an internal structure of stream attributeinformation;

FIG. 22 is a diagram showing steps for identifying video data;

FIG. 23 is a block diagram showing an example of a configuration of anintegrated circuit for implementing the moving picture coding method andthe moving picture decoding method according to each of the embodiments;

FIG. 24 is a diagram showing a configuration for switching betweendriving frequencies;

FIG. 25 is a diagram showing steps for identifying video data andswitching between driving frequencies;

FIG. 26 is a diagram showing an example of a look-up table in whichvideo data standards are associated with driving frequencies;

FIG. 27A is a diagram showing an example of a configuration for sharinga module of a signal processing unit;

FIG. 27B is a diagram showing another example of a configuration forsharing a module of the signal processing unit;

FIG. 28A is a correspondence between slice type SliceType and a ctxIdxnumber which corresponds to a probability value necessary for arithmeticcoding and arithmetic decoding;

FIG. 28B is a table for defining combinations of ctxIdx numbers 0 to 11as illustrated in FIG. 28A and information (m, n) necessary fordetermining an initial probability;

FIG. 28C is a table which indicates allocation of an offset valuectsIdxOffset which defines that the foremost ctxIdx is changed accordingto a slice type;

FIG. 28D is a table how ctxIdx is allocated to binIdx which is a numberindicating an order from the foremost of the binary signal sequence;

FIG. 29A is a diagram showing how to obtain ctxIdxInc which is a signalfor deriving a ctxIdx number with respect to a flag including aluminance CBF flag in HEVC;

FIG. 29B is a table showing how to determine ctxIdxInc of the luminanceCBF flag;

FIG. 30 is a chart showing a flow of the conventional context adaptivedecoding processes;

FIG. 31 is a chart showing a flow of the conventional bypass arithmeticdecoding processes; and

FIG. 32 is a flowchart for explaining in more detail normalizationprocessing (RenormD) as illustrated in Step SC08 in FIG. 30.

DESCRIPTION OF EMBODIMENTS

(Underlying Knowledge Forming Basis of the Present Disclosure)

In the above described process (d), the present video coding standardsand the video coding standards under consideration further reduce anamount of information by coding a flag which indicates whether or notthere is information in the residual block after Fourier transform andquantization. More specifically, the flag which indicates whether or notthere is a coefficient in the residual block after quantization isvariable length coded.

It should be noted that in a candidate standard called High EfficiencyVideo Coding (HEVC) in which progress is being made in work towardstandardization (refer to Non Patent Literature 2), this identificationflag is called coded block flag (CBF) and the identification flagcorresponding to a luminance signal is called luminance CBF flagcbf_luma. In the variable length coding, Context Adaptive BinaryArithmetic Coding (CABAC) based on arithmetic coding to be describedlater is known, and in HEVC, coding is performed with parameters definedby a method shown in FIGS. 28A to 29B.

FIGS. 28A to 28D are an information group showing the definition ofinformation for coding luminance CBF flag in HEVC. First, Table 0000 asillustrated in FIG. 28A shows correspondence between a type of slice(I/P/B) called SliceType, and a ctxIdx number corresponding to aprobability value necessary for arithmetic coding and arithmeticdecoding. This shows, for example, in the case of I slice, that ctxIdxnumbers used for coding and decoding of the luminance CBF flag are fourkinds, that is, 0 to 3. Similarly, this shows four kinds, that is, 4 to7 in the case of P slice, and four kinds, that is, 8 to 11 in the caseof B slice.

Next, Table 0001 shown in FIG. 28B is a table for defining a combinationof ctxIdx numbers 0 to 11 shown in Table 0000 and information (m, n)necessary for determining an initial probability. It should be notedthat regarding a technique for deriving the initial probability with theuse of (m, n), a technique disclosed in Non Patent Literature 1 or NonPatent Literature 2 is used.

Next, Table 0002 shown in FIG. 28C is a table which shows an allocationof an offset value ctxIdxOffset which defines a change of the foremostctxIdx according to the SliceType (in example, 0, 4, and 8).

Next, Table 0003 shown in FIG. 28D is a table which shows how toallocate ctxIdx with respect to binIdx which is a number showing anorder from the foremost of the binary signal sequence because ctxIdx isallocated to every binary signal sequence (bin) when the arithmeticcoding and decoding are actually performed. In other words, the firstbit of the first binary signal sequence is determined as binIdx=0, andhereafter is defined as 1 and 2. It should be noted that since theluminance CBF flag is a flag indicating “0” or “1”, it is defined onlyin the case of bixIdx =0. A method defined in subclause 9.3.3.1.1.1shows that the ctxIdx number is used with one of 0, 1, 2, and 3 and isprovided with an offset of 0, 4, and 8 according to SliceType. It shouldbe noted that na in the table is a sign of not available.

Moreover, the content of the subclause 9.3.1.1.1 will be described indetail with reference to FIGS. 29A and 29B. B01 shown in FIG. 29A is anextracted portion from Non-Patent Literature 2 of a portion which showsa method for obtaining a signal ctxIdxInc for deriving the ctxIdx numberwith respect to a flag including the luminance CBF flag in HEVC.

First, 9.3.3.1.1 shows arithmetic coding is performed on a flagincluding the luminance CBF flag, based on results of neighboringblocks. Next, in a portion of 9.3.3.1.1.1, details about derivation of ablock result located above the block including a flag of the codingtarget and a block result located in the left are described. It shouldbe noted that in the luminance CBF flag, as illustrated in Table 9-50shown in FIG. 29B, it is shown that ctxIdxInc is determined as followsby the luminance CBF flag in the left block and the luminance CBF flagin the above block.

First, in the case where the luminance CBF flag in the left block is 0(or does not exist) and the luminance CBF flag in the above block is 0(or does not exist), the ctxIdxInc number of the luminance CBF flag ofthe coding target is determined to be 0 (case 1). Moreover, in the casewhere the luminance CBF flag in the left block is 1 and the luminanceCBF flag in the above block is 0 (or does not exist), the ctxIdxIncnumber of the luminance CBF flag of the coding target is determined tobe 1 (case 2). Moreover, in the case where the luminance CBF flag in theleft block is 0 (or does not exist) and the luminance CBF flag in theabove block is 1, the ctxIdxInc number of the luminance CBF flag of thecoding target is determined to be 2 (case 3). Moreover, in the casewhere the luminance CBF flag in the left block is 1 and the luminanceCBF flag in the above block is 1, the ctxIdxInc number of the CBF flagof the coding target is determined to be 3 (case 4).

In this way, ctxIdxInc for deriving a probability value for use inarithmetic coding and arithmetic decoding of the luminance CBF flag ofthe coding target according to a value of the surrounding luminance CBFflag is switched.

Next, variable length coding of the identification flag (CBF) and thelike will be described. In H.264, as one of the variable length codingmethods, there is Context Adaptive Binary Arithmetic Coding (CABAC).CABAC will be described with reference to FIGS. 30 to 32.

FIG. 30 is a flowchart showing a flow of the above describedconventional context adaptive arithmetic decoding processes. It shouldbe noted that this diagram is extracted from Non Patent Literature 1 andis as described in Non Patent Literature 1 as long as there is nospecific explanation.

In the arithmetic decoding processing, a context (ctxIdx) determinedbased on the signal type is input first.

This is followed by: the calculation of a value qCodIRangeIdx derivedfrom a parameter codIRange showing a current internal state of thearithmetic decoding apparatus; the obtainment of a pStateIdx value thatis a state value corresponding to ctxIdx; and the obtainment ofcodIRangeLPS with reference to a table (rangeTableLPS) based on thesetwo values of qCodIRangeIdx and pStateIdx. Here, this codIRangeLPSdenotes a value that is a parameter showing the internal state of thearithmetic decoding apparatus at the time of the occurrence of an LPS(this LPS specifies one of the symbols 0 and 1 that has the loweroccurrence probability) with respect to a first parameter codIRangeshowing the internal state of the arithmetic decoding apparatus. Inaddition, a value obtained by subtracting the aforementionedcodIRangeLPS from the current codIRange is included in codIRange (StepSC01).

Next, the calculated codIRange is compared with a second parametercodIOffset showing the internal state of the arithmetic decodingapparatus (Step SC02). When the codIOffset is greater than or equal tocodIRange (YES in Step SC02), it is determined that the symbol of theLPS has occurred, and vaIMPS (an MPS value (0 or 1) specifying the oneof the symbols 0 and 1 which has the higher occurrence probability, andthe different value (0 when vaIMPM=1 is satisfied or 1 when vaIMPM=0 issatisfied) are set to binVal that is a decoding output value.

Moreover, a value obtained by subtracting codIRange is set to a secondparameter codIOffset showing the internal state of the arithmeticdecoding apparatus. Furthermore, a value of codIRangeLPS calculated inStep SC01 is set to the first parameter codIRange showing the internalstate of the arithmetic decoding apparatus (Step SC03) because LPS hasoccurred.

It should be noted that in the case where pStateIdx value which is astate value corresponding to the ctxIdx is 0 (YES in Step SC05), it isshown that the probability of LPS is greater than the probability ofMPS, and therefore vaIMPM is replaced (0 when vaIMPM=1 is satisfied or 1when vaIMPM=0 is satisfied) (Step SC06). Meanwhile, in the case wherethe pStateIdx value is 0 (NO in Step SC05), the pStateIdx value isupdated based on a transform table transIdxLPS in the case where the LPSoccurs (Step SC07).

Furthermore, in the case where codIOffset is small (NO in SC02), it isdetermined that the symbol of the MPS has occurred, and vaIMPS is set tobinVal that is a decoding output value, and the pStateIdx value isupdated based on the transform table transIdxMPS in the case where theMPS has occurred (Step SC04).

Lastly, normalization (RenormD) (Step SC08) is performed to end thearithmetic decoding.

As described the above, in the context adaptive binary arithmeticcoding, a plurality of symbol occurrence probabilities each of which isthe occurrence probability of a binary symbol and corresponds to contextindex are stored and the symbol occurrence probabilities are switchedaccording to a condition (for example, refer to the value of theadjacent block). Therefore, the order of processes needs to bemaintained.

FIG. 31 is a flowchart showing a flow of the above-describedconventional arithmetic decoding processes for bypass processing. Itshould be noted that this diagram is extracted from Non PatentLiterature 1 and is as described in Non Patent Literature 1 as long asthere is no specific explanation.

First, the second parameter codIOffset showing a current internal stateof the arithmetic decoding apparatus is shifted to the left (doubled),and 1 bit is read out from the bit stream. This (doubled) value is setwhen the read-out bit is 0, whereas a value obtained by adding 1 theretois set when the read-out bit is 1 (SD01).

Next, in the case where codIOffset is greater than or equal to the firstparameter codIRange showing the internal state of the arithmeticdecoding apparatus (YES in SD02), “1” is set to binVal that is adecoding output value, and a value obtained through the subtraction ofcodIRange is set to codIOffset (Step SD03). Meanwhile, in the case wherecodIOffset is smaller than the first parameter codIRange showing theinternal state of the arithmetic decoding apparatus (NO in SD02), “0” isset to binVal that is a decoding output value (Step SD04).

FIG. 32 is a flowchart for explaining in detail the normalizationprocessing (RenormD) shown in Step SC08 in FIG. 30. It should be notedthat this diagram is extracted from Non Patent Literature 1 and is asdescribed in Non Patent Literature 1 as long as there is no specificexplanation.

When the first parameter codIRange showing the internal state of thearithmetic decoding apparatus in arithmetic decoding is smaller than0×100 (in the hexadecimal notation that is 256 in the decimal system)(YES in Step SE01), codIRange is shifted to the left (doubled), thesecond parameter codIOffset showing the internal state of the arithmeticdecoding apparatus is shifted to the left (doubled), and 1 bit is readout from the bit stream. This (doubled) value is set when the read-outbit is 0, whereas a value obtained by adding 1 thereto is set when theread-out bit is 1 (SE02). This processing is completed when codIRangereaches or exceeds 256 at last (NO in Step SE01).

Arithmetic decoding is performed by performing the above processes.

However, the conventional technique requires that the probability valueis varied according to the results of the above and left blocks that areneighboring with each other for arithmetic coding and arithmeticdecoding of the luminance CBF flag. Against this backdrop, the resultsof neighboring blocks in the left and above portions for coding ordecoding should be recorded for arithmetic coding and arithmeticdecoding. Because of this, in the case where resolution of an inputvideo is large, a voluminous memory must be prepared for storing theresults.

In order to solve the above described problem, a moving picture codingmethod according to one non-limiting and exemplary embodiment is amethod for decoding a moving picture signal for each of the firstprocessing units. More specifically, the moving picture coding methodcomprising: transforming, for each of one or more second processingunits included in the first processing unit, the moving picture signalin a spatial domain into a frequency domain coefficient and quantizingthe frequency domain coefficient; and performing arithmetic coding on aluminance CBF flag indicating whether or not a quantized coefficient isincluded in each of the second processing units for which the transformand the quantization are performed. In the performing of arithmeticcoding, a probability table for use in the arithmetic coding isdetermined according to whether or not a size of the first processingunit is identical to a size of the second processing unit and whether ornot the second processing unit has a predetermined maximum size.

With this configuration, since a probability value for performingarithmetic coding of the luminance CBF flag can be determined withoutdepending on the value of the luminance CBF flag for each of thesurrounding blocks, a high coding efficiency can be maintained even if amemory capacity for holding the luminance CBF flag is significantlydecreased.

Furthermore, in the performing of arithmetic coding, a probability tablefor use in the arithmetic coding is further determined according to atype of a slice to which the first processing unit belongs.

For example, the first processing unit may be a coding unit. Moreover,the second processing unit may be a transform unit.

Moreover, switching may be performed between coding conforming to afirst standard and coding conforming to a second standard and thetransform and quantization and the arithmetic coding are performed asthe coding conforming to the first standard, and the moving picturecoding method may further comprise coding an identifier indicating acoding standard.

A moving picture decoding method according to one non-limiting andexemplary embodiment is a method for decoding a coded moving picturesignal for each of the first processing units. More specifically, themoving picture decoding method includes: performing arithmetic decodingon a luminance CBF flag indicating whether or not a quantizedcoefficient is included in one or more second processing units includedin the first processing unit; and reconstructing the moving picturesignal using the quantized coefficient of the second processing unitwhen the luminance CBF flag indicates that the quantized coefficient isincluded in each of the second processing units, the luminance CBF flagbeing decoded in the arithmetic decoding. In the performing ofarithmetic decoding, a probability table for use in the arithmeticdecoding is determined according to whether or not a size of the firstprocessing unit is identical to a size of the second processing unit andwhether or not the second processing unit has a predetermined maximumsize.

In the performing of arithmetic decoding, a probability table for use inthe arithmetic decoding is further determined according to a type of aslice to which the first processing unit belongs.

For example, the first processing unit may be a coding unit. Moreover,the second processing unit may be a transform unit.

Moreover, switching may be performed between decoding conforming to afirst standard and decoding conforming to a second standard according toan identifier which is included in a coded signal and indicates thefirst standard or the second standard, and the arithmetic decoding andthe reconstructing may be performed as the decoding conforming to thefirst standard when the identifier indicates the first standard.

A moving picture coding apparatus according to one non-limiting andexemplary embodiment codes a moving picture signal for each of the firstprocessing units. More specifically, the moving picture coding apparatuscomprising: a transform and quantization unit configured to transform,for each of one or more second processing units included in the firstprocessing unit, the moving picture signal in a spatial domain into afrequency domain coefficient and to quantize the frequency domaincoefficient; and an arithmetic coding unit configured to performarithmetic coding on a luminance CBF flag indicating whether or not aquantized coefficient is included in the second processing unitprocessed by the transform and quantization unit. The arithmetic codingunit is configured to determine a probability table for use in thearithmetic coding according to whether or not a size of the firstprocessing unit is identical to a size of the second processing unit andwhether or not the second processing unit has a predetermined maximumsize.

A moving picture decoding apparatus according to one non-limiting andexemplary embodiment decodes a coded moving picture signal for each ofthe first processing units. More specifically, the moving picturedecoding apparatus comprising: an arithmetic decoding unit configured toperform arithmetic decoding on a luminance CBF flag indicating whetheror not a quantized coefficient is included in one or more secondprocessing units included in the first processing unit; and areconstruction unit configured to reconstruct a moving picture signalusing the quantized coefficient of the second processing unit when theluminance CBF flag indicates that the quantized coefficient is includedin the second processing unit, the luminance CBF flag being processed bythe arithmetic decoding unit. The arithmetic decoding unit is configuredto determine a probability table for use in the arithmetic decodingaccording to whether or not a size of the first processing unit isidentical to a size of the second processing unit and whether or not thesecond processing unit has a predetermined maximum size.

A moving picture coding and decoding apparatus according to onenon-limiting and exemplary embodiment includes the moving picture codingapparatus and the moving picture decoding apparatus that are describedabove.

It should be noted that general or specific embodiments may beimplemented not only as a system, a method, an integrated circuit, acomputer program, or a recording medium, but also as an optionalcombination of a system, a method, an integrated circuit, a computerprogram, and a recording medium.

Hereinafter, certain exemplary embodiments are described in greaterdetail with reference to the accompanying Drawings. Each of theexemplary embodiments described below shows a general or specificexample. The numerical values, shapes, materials, structural elements,the arrangement and connection of the structural elements, steps, theprocessing order of the steps etc. shown in the following exemplaryembodiments are mere examples, and therefore do not limit the inventiveconcept, the scope of which is defined in the appended Claims and theirequivalents. The present disclosure is defined by the scope of claims.Therefore, among the structural elements in the following exemplaryembodiments, structural elements not recited in any one of theindependent claims defining the most generic part of the inventiveconcept are described as arbitrary structural elements.

Embodiment 1

A moving picture decoding apparatus according to Embodiment 1 decodes acoded moving picture signal for each of the first processing units.Therefore, the moving picture decoding apparatus includes: an arithmeticdecoding unit which performs arithmetic decoding on a luminance CBF flagindicating whether or not a quantized coefficient is included in each ofone or more second processing units included in the first processingunit; and a reconstruction unit which reconstructs a moving picturesignal using a quantized coefficient of the second processing unit whenthe luminance CBF flag decoded in the arithmetic decoding unit showsthat the quantized coefficient is included in the second processingunit.

The arithmetic decoding unit determines a probability table for use inarithmetic decoding according to whether or not a size of the firstprocessing unit is identical to a size of the second processing unit andwhether or not the second processing unit has a predetermined maximumsize. Furthermore, the arithmetic decoding unit may determine aprobability table according to a slice type to which the firstprocessing unit belongs (I slice/P slice/B slice). It should be notedthat “determining a probability table” can be paraphrased as “switchinga context”, for example.

A moving picture input into the moving picture decoding apparatus iscomposed of a plurality of pictures. Moreover, each of the pictures isdivided into a plurality of slices. Then the slice is coded or decodedaccording to each of the processing units. The processing unit includesa coding unit (CU), a prediction unit (PU), and a transform unit (TU).CU is a block of maximum 128×128 pixels and is a unit which correspondsto a conventional macroblock. PU is a fundamental unit for interprediction. TU is a fundamental unit for orthogonal transform, and thesize of TU is as small as or smaller than the size of CU. Hereafter, thecoding unit is described as a coded block and the transform unit isdescribed as a transform block.

The first processing unit according to the present embodiment is, forexample, a coded block (CU). Moreover, the second processing unitaccording to the present embodiment is, for example, a transform block(TU). There is a luminance CBF flag in each of the transform blocks andthe luminance CBF flag indicates whether or not there is a quantizedcoefficient in the transform block. It should be noted that “whether ornot there is a quantized coefficient in the transform block” can beparaphrased as whether or not there is a quantized coefficient to becoded. Furthermore, it can be paraphrased as whether or not there is anon-zero coefficient in the transform block.

FIG. 1 is a block diagram showing a functional configuration of adecoding apparatus including a luminance CBF flag decoding unitaccording to Embodiment 1 of the present disclosure.

A decoding apparatus 100 according to the present embodiment, as shownin FIG. 1, includes a luminance CBF decoding unit 101, a control unit102, a switch 103, a residual coefficient decoding unit 104, and aresidual signal reconstruction unit 105, and an addition unit 106. Thedecoding apparatus 100 reconstructs the luminance CBF flag from adecoding position information POS and an obtained bit stream BS, andoutputs a decoded image signal OUT from an image prediction signal PRED.

An operation of the luminance CBF decoding unit 101 according to thepresent embodiment will be described in detail with reference to FIG. 2.FIG. 2 is a flowchart showing a flow of operations of the luminance CBFdecoding unit 101 according to the present disclosure.

First, the luminance CBF decoding unit 101 obtains a target bit streamBS. Moreover, the control unit 102 obtains information POS indicatingwhere the luminance CBF flag to be a decoding target is as a size of acoded block and a transform coefficient, and outputs it to the luminanceCBF decoding unit 101.

Next, the luminance CBF decoding unit 101, from information obtainedfrom the control unit 102, determines (i) whether or not a size of atransform block showing the luminance CBF flag of the decoding target isthe same as that of a coded block, or (ii) whether or not, for example,the size of the transform block is the same as the maximum size of thetransform block (S201). It should be noted that information specifyingthe maximum size of the transform block is, for example, included in abit stream.

When at least one of the above described (i) and (ii) is satisfied (YESin S201), ctxIdxInc which is a number for prescribing probabilityinformation used for arithmetic decoding is set to 1 (S203). Meanwhile,when none of the above described (i) and (ii) are satisfied (NO inS201), ctxIdxInc which is a number for prescribing probabilityinformation for use in arithmetic decoding is set to 0 (S202). It shouldbe noted that the value set to ctxIdxInc is not limited to the examplesof Steps S202 and S203. In other words, it is acceptable as long as adifferent value is set for each of Step S202 and Step S203. Still, acommon value needs to be set to the coding side and the decoding side.

Next, a probability value is obtained which corresponds to ctxIdxobtained by adding ctxIdxInc which is a number for prescribing theprobability information obtained in Steps S202 and S203, and an offsetvalue (refer to FIGS. 5A to 5D to be described) which is determined foreach of the predetermined slices, and arithmetic decoding processing isperformed on the target luminance CBF flag (S204). With this, theluminance CBF flag is obtained.

Next, the luminance CBF flag obtained in Step S204 is output withrespect to the control unit 102 and is used for control of the switch103. In the case where the luminance CBF flag indicates “no coefficient”(for example 0), the switch 103 is connected to a terminal B. In otherwords, since there is no transform coefficient in the transform block,there is no residual signal to be added with respect to the imageprediction signal PRED. Therefore, the image prediction signal PRED isoutput as a decoding image signal OUT.

Meanwhile, in the case where the luminance CBF flag indicates“coefficient exists” (for example 1), the switch 103 is connected to aterminal A. In this case, the residual coefficient signal included inthe bit stream BS is decoded by the residual coefficient decoding unit104, and the residual signal obtained through inverse transform andinverse quantization by the residual signal reconstruction unit 105, andthe image prediction signal PRED are added by the addition unit 106, andthe decoding image signal OUT is output. With this, the decoding imagesignal OUT can be correctly output from the bit stream BS with the useof the luminance CBF flag.

In other words, the luminance CBF decoding unit 101 and the control unit102 shown in FIG. 1, for example, correspond to the arithmetic decodingunit according to the present embodiment. Moreover, the switch 103, theresidual coefficient decoding unit 104, and the residual signalreconstruction unit 105 shown in FIG. 1 correspond to the reconstructionunit according to the present embodiment. It should be noted that theyare not limited to the above described correspondence relationships.

FIG. 3 is a schematic view for explaining the condition shown in StepS201 of FIG. 2. Blocks 301 to 306 illustrated in thick frames denotecoded blocks. Moreover, blocks generated through further division ofblocks 301 and 302 denote transform blocks.

The size of the transform block is determined to be as large as orsmaller than the size of the coded block. It should be noted that inthis description, the case will be described where the size of blocks301 and 302 are the maximum size of the coded block (64×64 pixels) andthe maximum size of the transform block is determined to be a block sizesmaller by one hierarchical layer (32×32 pixels). Moreover, the maximumsize of the transform size is varied according to informationillustrated in slice header information.

It should be noted that since the present disclosure, regardless of thesize of the transform block, is characterized by switching probabilitytables according to a constant condition (Step S201) and not dependingon the results of the surrounding blocks, the present disclosure canrealize effects of the present disclosure (reduction in an amount ofmemory) even if there is a change in the maximum size of the transformblock.

Here, the case where the block 301 is determined as a coded block willbe described.

First, in the case where a small block of the first hierarchical layereach obtained through the division of the block 301 into four blocks isa transform block, the luminance CBF flag 311 corresponding to the smallblock of the first hierarchical layer is decoded. In the case where theluminance CBF flag 311 indicates no coefficient, the transformcoefficient is not included in the small block of the first hierarchicallayer. Therefore, the luminance CBF flags 312 and 313 corresponding tothe blocks smaller than this are not decoded. It should be noted that inthe case where the luminance CBF flag 311 is decoded, the small block ofthe first hierarchical layer becomes the maximum size of the transformblock (YES in S201 of FIG. 2). Therefore, ctxIdxInc=1 is used as anumber showing a probability table for use in arithmetic decoding of theluminance CBF flag (S203 in FIG. 2).

Meanwhile, in the case where a small block of the second hierarchicallayer (16×16 pixels) each obtained through the division of the blockinto four blocks is a transform block, the luminance CBF flag 312corresponding to the small block of the second hierarchical layer isdecoded. Moreover, in the case where a small block of the thirdhierarchical layer (8×8 pixels) each obtained through a further divisionof the block into four blocks is a transform block, the luminance CBFflag 313 corresponding to the small block of the third hierarchicallayer is decoded. In these cases, ctxIdxInc=0 is used as a numbershowing a probability table for use in arithmetic decoding of theluminance CBF flag (S202 in FIG. 2).

In the case where the luminance CBF flag (illustration is omitted)corresponding to the small block of the first hierarchical layer of theblock 302 is decoded, ctxIdxInc=1 is used as a number showing theprobability table, while in the case where the luminance CBF flag(illustration is omitted) corresponding to the small block of the secondand following hierarchies is decoded, ctxIdxInc=0 is used as a numbershowing the probability table. Furthermore, also with respect to blocks303 to 306, after it is determined whether or not the size of thetransform block is identical to the size of the coded block or themaximum size of the transform block, a number ctxIdxInc showing aprobability table is determined according to a determination result.

As described above, by switching between two kinds in which ctxIdxInc isdetermined as “0” or “1” based on a comparison between the size of thetransform block and the size of the coded block, the number ofprobability tables is reduced from the conventional 4 to 2 (per slice).Since there is no need of reference to the luminance CBF flag of thesurrounding block for determining ctxIdxInc of the luminance CBF flag ofthe decoding target, a voluminous amount of memory including line bufferdoes not have to be prepared. As a result, the luminance CBF flag can becorrectly decoded.

Moreover, by switching the probability table of the luminance CBF flagbetween two stages based on whether or not the size of the transformblock is maximum, a decrease in coding efficiency caused by a reductionin the number of probability tables can be limited. This is because theexistence or absence of a transform coefficient often depends on theblock size of the transform block. More specifically, this takesadvantage of a fact that a possibility is higher that all coefficientsbecome zero if the transform size is smaller.

It should be noted that an arithmetic decoding unit according toEmbodiment 1 of the present disclosure (a decoding apparatus 100) isincluded in a moving picture decoding apparatus which decodes codedimage data which are compressed and coded. FIG. 4 is a block diagramshowing an example of a configuration of a moving picture decodingapparatus 400 according to Embodiment 1 of the present disclosure.

The moving picture decoding apparatus 400 decodes coded image data whichare compressed and coded. For example, coded image data are input intothe image decoding apparatus 400 as a decoding target signal for each ofthe blocks. The image decoding apparatus 400 reconstructs image data byperforming variable length decoding, inverse quantization, and inversetransformation on the input decoding target signal.

As shown in FIG. 4, the moving picture decoding apparatus 400 includesan entropy decoding unit 410, an inverse quantization and inversetransform unit 420, an adder 425, a deblocking filter 430, a memory 440,an intra prediction unit 450, a motion compensation unit 460, and anintra/inter switch 470.

The entropy decoding unit 410 reconstructs quantized coefficients byperforming variable length decoding on an input signal (input stream).It should be noted here that the input signal (input stream) is adecoding target signal and corresponds to data for each of the blocks ofcoded image data. Moreover, the entropy decoding unit 410 obtains motiondata from the input signal, and outputs the obtained motion data to themotion compensation unit 460.

The inverse quantization and inverse transform unit 420 reconstructs thetransform coefficients by performing inverse quantization on thequantized coefficients reconstructed by the entropy decoding unit 410.Then, the inverse quantization and inverse transform unit 420reconstructs a prediction error by performing inverse transform on thereconstructed transform coefficients.

The adder 425 adds the prediction error reconstructed by the inversequantization and inverse transform unit 420 and a prediction signalobtained from the intra/inter switch 470 to generate a decoded image.

The deblocking filter 430 performs deblocking filtering on the decodedimage generated by the adder 425. The decoded image processed by thedeblocking filter is output as a decoded signal. The memory 440 is amemory for storing reference images for use in motion compensation. Morespecifically, the memory 440 stores decoded images in which a deblockingfilter process is performed by the deblocking filter 430.

The intra prediction unit 450 performs intra prediction to generate aprediction signal (an intra prediction signal). More specifically, theintra prediction unit 450 performs intra prediction with reference toimages surrounding the decoding target block (input signal) in thedecoded image generated by the adder 425 to generate an intra predictionsignal. The motion compensation unit 460 performs motion compensationbased on motion data output from the entropy decoding unit 410 togenerate a prediction signal (an inter prediction signal).

The intra/inter switch 470 selects any one of an intra prediction signaland an inter prediction signal, and outputs the selected signal as theprediction signal to the adder 425.

With the above structure, the moving picture decoding apparatus 400according to Embodiment 2 of the present disclosure decodes thecompression-coded image data.

It should be noted that in the moving picture decoding apparatus 400,the decoding unit of the luminance CBF flag according to Embodiment 1 ofthe present disclosure is included by the entropy decoding unit 410, theinverse quantization and inverse transform unit 420, and the adder 425.More specifically, for example, the luminance CBF decoding unit 101, thecontrol unit 102, the switch 103, the residual coefficient decoding unit104 in FIG. 1 are included in the entropy decoding unit 410, theresidual signal reconstruction unit 105 in FIG. 1 is included in theinverse quantization and inverse transform unit 420 in FIG. 4, and theaddition unit 106 in FIG. 1 is included in the adder 425 in FIG. 4. Itshould be noted that they are not limited to the above describedcorrespondence relationships.

As described above, the moving picture decoding apparatus and the movingpicture decoding method according to Embodiment 1 of the presentdisclosure make it possible to appropriately reconstruct a bit stream inwhich the need of a memory for decoding the luminance CBF is decreasedby performing arithmetic decoding on the luminance CBF flag of thedecoding target without depending on the value of the luminance CBF ofthe surrounding block.

FIGS. 5A. 5B, 5C and 5D each show an example of Tables 1000 to 1003 foruse in arithmetic decoding according to the present embodiment. Itshould be noted that Tables 1000 to 1003 are tables which correspond toFIGS. 28A to 28D, respectively. As shown in FIGS. 5A to 5D, in thepresent embodiment, two probability tables per slice are switched.Moreover, the result of the luminance CBF flag for each of thesurrounding blocks is not used for the switching of the probabilitytable. This will be further described with reference to FIG. 6.

FIG. 6 is sentences for explaining a method for obtaining ctxIdxIncwhich is a number for deriving the probability with respect to theluminance CBF flag according to the present embodiment. As illustratedhere, the switch of the two numbers depends on the block size of thetransform size (transformDepth and MaxTrafoSize) but does not depend onthe results of the surrounding blocks.

Embodiment 2

An outline of an arithmetic coding method according to the presentembodiment will be described. It should be noted that detaileddescriptions about portions similar to Embodiment 1 will be omitted andwill be focused on the differences.

The arithmetic coding method according the present embodiment does notconventionally use the result of the luminance CBF flag in surroundingblocks for coding the luminance CBF flag, but is characterized byswitching between two probability tables (per slice) according to thesize of the transform block. With this, a memory size necessary forcoding is significantly reduced.

An outline of the arithmetic coding method according to the presentembodiment has been described. In the case where there is no specificexplanation, it is shown that the same method as the conventionalarithmetic coding method may be taken.

A moving picture coding apparatus according to Embodiment 2 codes amoving picture signal for each of the first processing units. Morespecifically, the moving picture coding apparatus includes a transformand quantization unit which transforms a moving picture signal (forexample a residual signal) in a spatial domain into a frequency domaincoefficient and quantizes the frequency domain coefficient for each ofone or more second processing units included in the first processingunit, and an arithmetic coding unit which performs arithmetic coding ona luminance CBF flag indicating whether or not a quantized coefficientis included in the second processing unit processed by the transform andquantization unit.

Then, the arithmetic coding unit determines a probability table for usein arithmetic coding according to whether or not a size of the firstprocessing unit is identical to a size of the second processing unit andwhether or not the second processing unit has a predetermined maximumsize (a context is switched). The arithmetic coding unit may furtherdetermine a probability table for use in arithmetic coding according toa type to which the first processing unit belongs.

Next, a flow of processes by a luminance CBF flag coding unit performingthe luminance CBF flag coding method according to the present embodimentwill be described. FIG. 7 is a flowchart showing an example of a flow ofoperations of a luminance CBF flag coding unit according to Embodiment 2of the present disclosure.

The luminance CBF flag coding unit, from information obtained from thecontrol unit, determines (i) whether or not a size of a transform blockindicating the luminance CBF flag of the coding target is the same asthat of a coded block, or (ii) whether or not a size of a transformblock, for example, is the same as the maximum size of the transformblock (S701). It should be noted that information specifying the maximumsize of the transform block is, for example, included in a bit stream.

When at least one of (i) and (ii) is satisfied (YES in S701), ctxIdxIncwhich is a number for prescribing probability information for arithmeticcoding is set to 1 (S703). Meanwhile, when none of the above described(i) and (ii) are satisfied (NO in S701), ctxIdxInc which is a number forprescribing probability information used for arithmetic coding is set to0 (S702).

Next, a probability value is obtained which corresponds to ctxIdxobtained by adding ctxIdxInc which is a number for prescribing theprobability information obtained in Steps S702 and S703 and an offsetvalue (refer to FIGS. 5A to 5D) which is determined in advance for eachof the slices, and arithmetic coding processing is performed on thetarget luminance CBF flag (S704). With this, the luminance CBF flag iscoded.

By coding in this way, a coding apparatus of the luminance CBF flag witha limited required amount of memory can be realized.

It should be noted that a luminance CBF flag coding unit according toEmbodiment 2 of the present disclosure is included in an image codingapparatus which performs compression coding on image data. FIG. 8 is ablock diagram showing an example of a configuration of an image codingapparatus 200 according to Embodiment 2 of the present disclosure.

The image coding apparatus 200 performs compression coding on imagedata. For example, image data are input into the image coding apparatus200 as an input signal for each of the blocks. The image codingapparatus 200 performs transform, quantization, and variable lengthcoding on the input signal to generate a coded signal.

As shown in FIG. 10, the image coding apparatus 200 includes asubtractor 205, a transform and quantization unit 210, an entropy codingunit 220, an inverse quantization and inverse transform unit 230, anadder 235, a deblocking filter 240, a memory 250, an intra predictionunit 260, a motion estimation unit 270, a motion compensation unit 280,and an intra/inter switch 290.

The subtractor 205 calculates a prediction error that is the differencebetween the input signal and the prediction signal.

The transform and quantization unit 210 transforms the prediction errorin the spatial domain into transform coefficients in the frequencydomain. For example, the transform and quantization unit 210 performsDiscrete Cosine Transform (DCT) on the prediction error to generatetransform coefficients. Furthermore, the transform and quantization unit210 quantizes the transform coefficients to generate quantizedcoefficients.

Moreover, the transform and quantization unit 210 generates a luminanceCBF flag indicating whether or not a coefficient (quantized coefficient)is present in the transform block. More specifically, the transform andquantization unit 210 sets “1” to the luminance CBF flag when acoefficient is present in the transform block and sets “0” to theluminance CBF flag when a coefficient is not present in the transformblock.

The entropy coding unit 220 performs variable length coding on thequantized coefficient to generate a coded signal. In addition, theentropy coding unit 220 codes motion data (for example a motion vector)estimated by the motion estimation unit 270, adds the motion data to thecoded signal, and outputs the coded signal.

The inverse quantization and inverse transform unit 230 reconstructs thetransform coefficients by performing inverse quantization on thequantized coefficients. Furthermore, the inverse quantization andinverse transform unit 230 reconstructs a prediction error by performinginverse transform of the reconstructed transform coefficients. Here, thereconstructed prediction error has lost information through thequantization, and thus does not match the prediction error that isgenerated by the subtractor 205. In other words, the reconstructedprediction error includes a quantization error.

The adder 235 adds the reconstructed prediction error and the predictionsignal to generate a local decoded image.

The deblocking filter 240 performs deblocking filtering on the generatedlocal decoded image.

The memory 250 is a memory for storing reference images for use inmotion compensation. More specifically, the memory 250 stores the localdecoded images processed by the deblocking filter.

The intra prediction unit 260 performs intra prediction to generate aprediction signal (an intra prediction signal). More specifically, theintra prediction unit 260 performs intra prediction with reference toimages surrounding the coding target block (input signal) in the localdecoded image generated by the adder 235 to generate an intra predictionsignal.

The motion estimation unit 270 estimates motion data (for example amotion vector) between the input signal and a reference image stored inthe memory 250.

The motion compensation unit 280 performs motion compensation based onthe estimated motion data to generate a prediction signal (an interprediction signal).

The intra/inter switch 290 selects any one of an intra prediction signaland an inter prediction signal, and outputs the selected signal as theprediction signal to the subtractor 205 and the adder 235.

With this structure, the image coding apparatus 200 according toEmbodiment 2 of the present disclosure compression codes the image data.

It should be noted that in the moving picture coding apparatus 200, theCBF flag coding unit is, for example, included in the entropy codingunit 220. In other words, the CBF flag coding unit included in theentropy coding unit 220 performs arithmetic coding on the luminance CBFflag generated by the transform and quantization unit 210. It should benoted that it is not limited to the above described correspondencerelationship.

Embodiment 3

The processing described in each of embodiments can be simplyimplemented in an independent computer system, by recording, in arecording medium, a program for implementing the configurations of themoving picture coding method (image coding method) and the movingpicture decoding method described (image decoding method) in each ofembodiments. The recording media may be any recording media as long asthe program can be recorded, such as a magnetic disk, an optical disk, amagnetic optical disk, an IC card, and a semiconductor memory.

Hereinafter, the applications to the moving picture coding method (imagecoding method) and the moving picture decoding method described (imagedecoding method) in each of embodiments and systems using thereof willbe described. The system has a feature of having an image coding anddecoding apparatus that includes an image coding apparatus using theimage coding method and an image decoding apparatus using the imagedecoding method. Other configurations in the system can be changed asappropriate depending on the cases.

FIG. 9 illustrates an overall configuration of a content providingsystem ex100 for implementing content distribution services. The areafor providing communication services is divided into cells of desiredsize, and base stations ex106, ex107, ex108, ex109, and ex110 which arefixed wireless stations are placed in each of the cells.

The content providing system ex100 is connected to devices, such as acomputer ex111, a personal digital assistant (PDA) ex112, a cameraex113, a cellular phone ex114 and a game machine ex115, via the Internetex101, an Internet service provider ex102, a telephone network ex104, aswell as the base stations ex106 to ex110, respectively.

However, the configuration of the content providing system ex100 is notlimited to the configuration shown in FIG. 9, and a combination in whichany of the elements are connected is acceptable. In addition, eachdevice may be directly connected to the telephone network ex104, ratherthan via the base stations ex106 to ex110 which are the fixed wirelessstations. Furthermore, the devices may be interconnected to each othervia a short distance wireless communication and others.

The camera ex113, such as a digital video camera, is capable ofcapturing video. A camera ex116, such as a digital camera, is capable ofcapturing both still images and video. Furthermore, the cellular phoneex114 may be the one that meets any of the standards such as GlobalSystem for Mobile Communications (GSM) (registered trademark), CodeDivision Multiple Access (CDMA), Wideband-Code Division Multiple Access(W-CDMA), Long Term Evolution (LTE), and High Speed Packet Access(HSPA). Alternatively, the cellular phone ex114 may be a PersonalHandyphone System (PHS).

In the content providing system ex100, a streaming server ex103 isconnected to the camera ex113 and others via the telephone network ex104and the base station ex109, which enables distribution of images of alive show and others. In such a distribution, a content (for example,video of a music live show) captured by the user using the camera ex113is coded as described above in each of embodiments (i.e., the camerafunctions as the image coding apparatus according to an aspect of thepresent disclosure), and the coded content is transmitted to thestreaming server ex103. On the other hand, the streaming server ex103carries out stream distribution of the transmitted content data to theclients upon their requests. The clients include the computer ex111, thePDA ex112, the camera ex113, the cellular phone ex114, and the gamemachine ex115 that are capable of decoding the above-mentioned codeddata. Each of the devices that have received the distributed datadecodes and reproduces the coded data (i.e., functions as the imagedecoding apparatus according to an aspect of the present disclosure).

The captured data may be coded by the camera ex113 or the streamingserver ex103 that transmits the data, or the coding processes may beshared between the camera ex113 and the streaming server ex103.Similarly, the distributed data may be decoded by the clients or thestreaming server ex103, or the decoding processes may be shared betweenthe clients and the streaming server ex103. Furthermore, the data of thestill images and video captured by not only the camera ex113 but alsothe camera ex116 may be transmitted to the streaming server ex103through the computer ex111. The coding processes may be performed by thecamera ex116, the computer ex111, or the streaming server ex103, orshared among them.

Furthermore, the coding and decoding processes may be performed by anLSI ex500 generally included in each of the computer ex111 and thedevices. The LSI ex500 may be configured of a single chip or a pluralityof chips. Software for coding and decoding video may be integrated intosome type of a recording medium (such as a CD-ROM, a flexible disk, anda hard disk) that is readable by the computer ex111 and others, and thecoding and decoding processes may be performed using the software.Furthermore, when the cellular phone ex114 is equipped with a camera,the video data obtained by the camera may be transmitted. Furthermore,when the cellular phone ex114 is equipped with a camera, the video dataobtained by the camera may be transmitted. The video data is data codedby the LSI ex500 included in the cellular phone ex114.

Furthermore, the streaming server ex103 may be composed of servers andcomputers, and may decentralize data and process the decentralized data,record, or distribute data.

As described above, the clients may receive and reproduce the coded datain the content providing system ex100. In other words, the clients canreceive and decode information transmitted by the user, and reproducethe decoded data in real time in the content providing system ex100, sothat the user who does not have any particular right and equipment canimplement personal broadcasting.

Aside from the example of the content providing system ex100, at leastone of the moving picture coding apparatus (image coding apparatus) andthe moving picture decoding apparatus (image decoding apparatus)described in each of embodiments may be implemented in a digitalbroadcasting system ex200 illustrated in FIG. 10. More specifically, abroadcast station ex201 communicates or transmits, via radio waves to abroadcast satellite ex202, multiplexed data obtained by multiplexingaudio data and others onto video data. The video data is data coded bythe moving picture coding method described in each of embodiments (i.e.,data coded by the image coding apparatus according to an aspect of thepresent disclosure). Upon receipt of the multiplexed data, the broadcastsatellite ex202 transmits radio waves for broadcasting. Then, a home-useantenna ex204 with a satellite broadcast reception function receives theradio waves. Next, a device such as a television (receiver) ex300 and aset top box (STB) ex217 decodes the received multiplexed data, andreproduces the decoded data (i.e., functions as the image decodingapparatus according to an aspect of the present disclosure).

Furthermore, a reader/recorder ex218 (i) reads and decodes themultiplexed data recorded on a recording medium ex215, such as a DVD anda BD, or (ii) codes video signals in the recording medium ex215, and insome cases, writes data obtained by multiplexing an audio signal on thecoded data. The reader/recorder ex218 can include the moving picturedecoding apparatus or the moving picture coding apparatus as shown ineach of embodiments. In this case, the reproduced video signals aredisplayed on the monitor ex219, and can be reproduced by another deviceor system using the recording medium ex215 on which the multiplexed datais recorded. It is also possible to implement the moving picturedecoding apparatus in the set top box ex217 connected to the cable ex203for a cable television or to the antenna ex204 for satellite and/orterrestrial broadcasting, so as to display the video signals on themonitor ex219 of the television ex300. The moving picture decodingapparatus may be implemented not in the set top box but in thetelevision.

FIG. 11 illustrates the television (receiver) ex300 that uses the movingpicture coding method and the moving picture decoding method describedin each of embodiments. The television ex300 includes: a tuner ex301that obtains or provides multiplexed data obtained by multiplexing audiodata onto video data, through the antenna ex204 or the cable ex203, etc.that receives a broadcast; a modulation/demodulation unit ex302 thatdemodulates the received multiplexed data or modulates data intomultiplexed data to be supplied outside; and amultiplexing/demultiplexing unit ex303 that demultiplexes the modulatedmultiplexed data into video data and audio data, or multiplexes videodata and audio data coded by a signal processing unit ex306 into data.

The television ex300 further includes: a signal processing unit ex306including an audio signal processing unit ex304 and a video signalprocessing unit ex305 that decode audio data and video data and codeaudio data and video data, respectively (which function as the imagecoding apparatus and the image decoding apparatus according to theaspects of the present disclosure); and an output unit ex309 including aspeaker ex307 that provides the decoded audio signal, and a display unitex308 that displays the decoded video signal, such as a display.Furthermore, the television ex300 includes an interface unit ex317including an operation input unit ex312 that receives an input of a useroperation. Furthermore, the television ex300 includes a control unitex310 that controls overall each constituent element of the televisionex300, and a power supply circuit unit ex311 that supplies power to eachof the elements. Other than the operation input unit ex312, theinterface unit ex317 may include: a bridge ex313 that is connected to anexternal device, such as the reader/recorder ex218; a slot unit ex314for enabling attachment of the recording medium ex216, such as an SDcard; a driver ex315 to be connected to an external recording medium,such as a hard disk; and a modem ex316 to be connected to a telephonenetwork. Here, the recording medium ex216 can electrically recordinformation using a non-volatile/volatile semiconductor memory elementfor storage. The constituent elements of the television ex300 areconnected to each other through a synchronous bus.

First, the configuration in which the television ex300 decodesmultiplexed data obtained from outside through the antenna ex204 andothers and reproduces the decoded data will be described. In thetelevision ex300, upon a user operation through a remote controllerex220 and others, the multiplexing/demultiplexing unit ex303demultiplexes the multiplexed data demodulated by themodulation/demodulation unit ex302, under control of the control unitex310 including a CPU. Furthermore, the audio signal processing unitex304 decodes the demultiplexed audio data, and the video signalprocessing unit ex305 decodes the demultiplexed video data, using thedecoding method described in each of embodiments, in the televisionex300. The output unit ex309 provides the decoded video signal and audiosignal outside, respectively. When the output unit ex309 provides thevideo signal and the audio signal, the signals may be temporarily storedin buffers ex318 and ex319, and others so that the signals arereproduced in synchronization with each other. Furthermore, thetelevision ex300 may read multiplexed data not through a broadcast andothers but from the recording media ex215 and ex216, such as a magneticdisk, an optical disk, and a SD card. Next, a configuration in which thetelevision ex300 codes an audio signal and a video signal, and transmitsthe data outside or writes the data on a recording medium will bedescribed. In the television ex300, upon a user operation through theremote controller ex220 and others, the audio signal processing unitex304 codes an audio signal, and the video signal processing unit ex305codes a video signal, under control of the control unit ex310 using thecoding method described in each of embodiments. Themultiplexing/demultiplexing unit ex303 multiplexes the coded videosignal and audio signal, and provides the resulting signal outside. Whenthe multiplexing/demultiplexing unit ex303 multiplexes the video signaland the audio signal, the signals may be temporarily stored in thebuffers ex320 and ex321, and others so that the signals are reproducedin synchronization with each other. Here, the buffers ex318, ex319,ex320, and ex321 may be plural as illustrated, or at least one buffermay be shared in the television ex300. Furthermore, data may be storedin a buffer so that the system overflow and underflow may be avoidedbetween the modulation/demodulation unit ex302 and themultiplexing/demultiplexing unit ex303, for example.

Furthermore, the television ex300 may include a configuration forreceiving an AV input from a microphone or a camera other than theconfiguration for obtaining audio and video data from a broadcast or arecording medium, and may code the obtained data. Although thetelevision ex300 can code, multiplex, and provide outside data in thedescription, it may be capable of only receiving, decoding, andproviding outside data but not the coding, multiplexing, and providingoutside data.

Furthermore, when the reader/recorder ex218 reads or writes multiplexeddata from or on a recording medium, one of the television ex300 and thereader/recorder ex218 may decode or code the multiplexed data, and thetelevision ex300 and the reader/recorder ex218 may share the decoding orcoding.

As an example, FIG. 12 illustrates a configuration of an informationreproducing/recording unit ex400 when data is read or written from or onan optical disk. The information reproducing/recording unit ex400includes constituent elements ex401, ex402, ex403, ex404, ex405, ex406,and ex407 to be described hereinafter. The optical head ex401 irradiatesa laser spot in a recording surface of the recording medium ex215 thatis an optical disk to write information, and detects reflected lightfrom the recording surface of the recording medium ex215 to read theinformation. The modulation recording unit ex402 electrically drives asemiconductor laser included in the optical head ex401, and modulatesthe laser light according to recorded data. The reproductiondemodulating unit ex403 amplifies a reproduction signal obtained byelectrically detecting the reflected light from the recording surfaceusing a photo detector included in the optical head ex401, anddemodulates the reproduction signal by separating a signal componentrecorded on the recording medium ex215 to reproduce the necessaryinformation. The buffer ex404 temporarily holds the information to berecorded on the recording medium ex215 and the information reproducedfrom the recording medium ex215. The disk motor ex405 rotates therecording medium ex215. The servo control unit ex406 moves the opticalhead ex401 to a predetermined information track while controlling therotation drive of the disk motor ex405 so as to follow the laser spot.The system control unit ex407 controls overall the informationreproducing/recording unit ex400. The reading and writing processes canbe implemented by the system control unit ex407 using variousinformation stored in the buffer ex404 and generating and adding newinformation as necessary, and by the modulation recording unit ex402,the reproduction demodulating unit ex403, and the servo control unitex406 that record and reproduce information through the optical headex401 while being operated in a coordinated manner. The system controlunit ex407 includes, for example, a microprocessor, and executesprocessing by causing a computer to execute a program for read andwrite.

Although the optical head ex401 irradiates a laser spot in thedescription, it may perform high-density recording using near fieldlight.

FIG. 13 illustrates the recording medium ex215 that is the optical disk.On the recording surface of the recording medium ex215, guide groovesare spirally formed, and an information track ex230 records, in advance,address information indicating an absolute position on the diskaccording to change in a shape of the guide grooves. The addressinformation includes information for determining positions of recordingblocks ex231 that are a unit for recording data. Reproducing theinformation track ex230 and reading the address information in anapparatus that records and reproduces data can lead to determination ofthe positions of the recording blocks. Furthermore, the recording mediumex215 includes a data recording area ex233, an inner circumference areaex232, and an outer circumference area ex234. The data recording areaex234 is an area for use in recording the user data. The innercircumference area ex232 and the outer circumference area ex234 that areinside and outside of the data recording area ex233, respectively arefor specific use except for recording the user data. The informationreproducing/recording unit 400 reads and writes coded audio, coded videodata, or multiplexed data obtained by multiplexing the coded audio andvideo data, from and on the data recording area ex233 of the recordingmedium ex215.

Although an optical disk having a layer, such as a DVD and a BD isdescribed as an example in the description, the optical disk is notlimited to such, and may be an optical disk having a multilayerstructure and capable of being recorded on a part other than thesurface. Furthermore, the optical disk may have a structure formultidimensional recording/reproduction, such as recording ofinformation using light of colors with different wavelengths in the sameportion of the optical disk and for recording information havingdifferent layers from various angles.

Furthermore, a car ex210 having an antenna ex205 can receive data fromthe satellite ex202 and others, and reproduce video on a display devicesuch as a car navigation system ex211 set in the car ex210, in thedigital broadcasting system ex200. Here, a configuration of the carnavigation system ex211 will be a configuration, for example, includinga GPS receiving unit from the configuration illustrated in FIG. 11. Thesame will be true for the configuration of the computer ex111, thecellular phone ex114, and others.

FIG. 14A illustrates the cellular phone ex114 that uses the movingpicture coding method and the moving picture decoding method describedin embodiments. The cellular phone ex114 includes: an antenna ex350 fortransmitting and receiving radio waves through the base station ex110; acamera unit ex365 capable of capturing moving and still images; and adisplay unit ex358 such as a liquid crystal display for displaying thedata such as decoded video captured by the camera unit ex365 or receivedby the antenna ex350. The cellular phone ex114 further includes: a mainbody unit including an operation key unit ex366; an audio output unitex357 such as a speaker for output of audio; an audio input unit ex356such as a microphone for input of audio; a memory unit ex367 for storingcaptured video or still pictures, recorded audio, coded or decoded dataof the received video, the still pictures, e-mails, or others; and aslot unit ex364 that is an interface unit for a recording medium thatstores data in the same manner as the memory unit ex367.

Next, an example of a configuration of the cellular phone ex114 will bedescribed with reference to FIG. 14B. In the cellular phone ex114, amain control unit ex360 designed to control overall each unit of themain body including the display unit ex358 as well as the operation keyunit ex366 is connected mutually, via a synchronous bus ex370, to apower supply circuit unit ex361, an operation input control unit ex362,a video signal processing unit ex355, a camera interface unit ex363, aliquid crystal display (LCD) control unit ex359, amodulation/demodulation unit ex352, a multiplexing/demultiplexing unitex353, an audio signal processing unit ex354, the slot unit ex364, andthe memory unit ex367.

When a call-end key or a power key is turned ON by a user's operation,the power supply circuit unit ex361 supplies the respective units withpower from a battery pack so as to activate the cell phone ex114.

In the cellular phone ex114, the audio signal processing unit ex354converts the audio signals collected by the audio input unit ex356 invoice conversation mode into digital audio signals under the control ofthe main control unit ex360 including a CPU, ROM, and RAM. Then, themodulation/demodulation unit ex352 performs spread spectrum processingon the digital audio signals, and the transmitting and receiving unitex351 performs digital-to-analog conversion and frequency conversion onthe data, so as to transmit the resulting data via the antenna ex350.Also, in the cellular phone ex114, the transmitting and receiving unitex351 amplifies the data received by the antenna ex350 in voiceconversation mode and performs frequency conversion and theanalog-to-digital conversion on the data. Then, themodulation/demodulation unit ex352 performs inverse spread spectrumprocessing on the data, and the audio signal processing unit ex354converts it into analog audio signals, so as to output them via theaudio output unit ex357.

Furthermore, when an e-mail in data communication mode is transmitted,text data of the e-mail inputted by operating the operation key unitex366 and others of the main body is sent out to the main control unitex360 via the operation input control unit ex362. The main control unitex360 causes the modulation/demodulation unit ex352 to perform spreadspectrum processing on the text data, and the transmitting and receivingunit ex351 performs the digital-to-analog conversion and the frequencyconversion on the resulting data to transmit the data to the basestation ex110 via the antenna ex350. When an e-mail is received,processing that is approximately inverse to the processing fortransmitting an e-mail is performed on the received data, and theresulting data is provided to the display unit ex358.

When video, still images, or video and audio in data communication modeis or are transmitted, the video signal processing unit ex355 compressesand codes video signals supplied from the camera unit ex365 using themoving picture coding method shown in each of embodiments (i.e.,functions as the image coding apparatus according to the aspect of thepresent disclosure), and transmits the coded video data to themultiplexing/demultiplexing unit ex353. In contrast, during when thecamera unit ex365 captures video, still images, and others, the audiosignal processing unit ex354 codes audio signals collected by the audioinput unit ex356, and transmits the coded audio data to themultiplexing/demultiplexing unit ex353.

The multiplexing/demultiplexing unit ex353 multiplexes the coded videodata supplied from the video signal processing unit ex355 and the codedaudio data supplied from the audio signal processing unit ex354, using apredetermined method. Then, the modulation/demodulation unit(modulation/demodulation circuit unit) ex352 performs spread spectrumprocessing on the multiplexed data, and the transmitting and receivingunit ex351 performs digital-to-analog conversion and frequencyconversion on the data so as to transmit the resulting data via theantenna ex350.

When receiving data of a video file which is linked to a Web page andothers in data communication mode or when receiving an e-mail with videoand/or audio attached, in order to decode the multiplexed data receivedvia the antenna ex350, the multiplexing/demultiplexing unit ex353demultiplexes the multiplexed data into a video data bit stream and anaudio data bit stream, and supplies the video signal processing unitex355 with the coded video data and the audio signal processing unitex354 with the coded audio data, through the synchronous bus ex370. Thevideo signal processing unit ex355 decodes the video signal using amoving picture decoding method corresponding to the moving picturecoding method shown in each of embodiments (i.e., functions as the imagedecoding apparatus according to the aspect of the present disclosure),and then the display unit ex358 displays, for instance, the video andstill images included in the video file linked to the Web page via theLCD control unit ex359. Furthermore, the audio signal processing unitex354 decodes the audio signal, and the audio output unit ex357 providesthe audio.

Furthermore, similarly to the television ex300, a terminal such as thecellular phone ex114 probably have 3 types of implementationconfigurations including not only (i) a transmitting and receivingterminal including both a coding apparatus and a decoding apparatus, butalso (ii) a transmitting terminal including only a coding apparatus and(iii) a receiving terminal including only a decoding apparatus. Althoughthe digital broadcasting system ex200 receives and transmits themultiplexed data obtained by multiplexing audio data onto video data inthe description, the multiplexed data may be data obtained bymultiplexing not audio data but character data related to video ontovideo data, and may be not multiplexed data but video data itself.

As such, the moving picture coding method and the moving picturedecoding method in each of embodiments can be used in any of the devicesand systems described. Thus, the advantages described in each ofembodiments can be obtained.

Furthermore, various modifications and revisions can be made in any ofthe embodiments in the present disclosure.

Embodiment 4

Video data can be generated by switching, as necessary, between (i) themoving picture coding method or the moving picture coding apparatusshown in each of embodiments and (ii) a moving picture coding method ora moving picture coding apparatus in conformity with a differentstandard, such as MPEG-2, MPEG-4 AVC, and VC-1.

Here, when a plurality of video data that conforms to the differentstandards is generated and is then decoded, the decoding methods need tobe selected to conform to the different standards. However, since towhich standard each of the plurality of the video data to be decodedconform cannot be detected, there is a problem that an appropriatedecoding method cannot be selected.

In order to solve the problem, multiplexed data obtained by multiplexingaudio data and others onto video data has a structure includingidentification information indicating to which standard the video dataconforms. The specific structure of the multiplexed data including thevideo data generated in the moving picture coding method and by themoving picture coding apparatus shown in each of embodiments will behereinafter described. The multiplexed data is a digital stream in theMPEG-2 Transport Stream format.

FIG. 15 illustrates a structure of the multiplexed data. As illustratedin FIG. 15, the multiplexed data can be obtained by multiplexing atleast one of a video stream, an audio stream, a presentation graphicsstream (PG), and an interactive graphics stream. The video streamrepresents primary video and secondary video of a movie, the audiostream (IG) represents a primary audio part and a secondary audio partto be mixed with the primary audio part, and the presentation graphicsstream represents subtitles of the movie. Here, the primary video isnormal video to be displayed on a screen, and the secondary video isvideo to be displayed on a smaller window in the primary video.Furthermore, the interactive graphics stream represents an interactivescreen to be generated by arranging the GUI components on a screen. Thevideo stream is coded in the moving picture coding method or by themoving picture coding apparatus shown in each of embodiments, or in amoving picture coding method or by a moving picture coding apparatus inconformity with a conventional standard, such as MPEG-2, MPEG-4 AVC, andVC-1. The audio stream is coded in accordance with a standard, such asDolby-AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, and linear PCM.

Each stream included in the multiplexed data is identified by PID. Forexample, 0x1011 is allocated to the video stream to be used for video ofa movie, 0x1100 to 0x111F are allocated to the audio streams, 0x1200 to0x121F are allocated to the presentation graphics streams, 0x1400 to0x141F are allocated to the interactive graphics streams, 0x1B00 to0x1B1F are allocated to the video streams to be used for secondary videoof the movie, and 0x1A00 to 0x1A1F are allocated to the audio streams tobe used for the secondary audio to be mixed with the primary audio.

FIG. 16 schematically illustrates how data is multiplexed. First, avideo stream ex235 composed of video frames and an audio stream ex238composed of audio frames are transformed into a stream of PES packetsex236 and a stream of PES packets ex239, and further into TS packetsex237 and TS packets ex240, respectively. Similarly, data of apresentation graphics stream ex241 and data of an interactive graphicsstream ex244 are transformed into a stream of PES packets ex242 and astream of PES packets ex245, and further into TS packets ex243 and TSpackets ex246, respectively. These TS packets are multiplexed into astream to obtain multiplexed data ex247.

FIG. 17 illustrates how a video stream is stored in a stream of PESpackets in more detail. The first bar in FIG. 17 shows a video framestream in a video stream. The second bar shows the stream of PESpackets. As indicated by arrows denoted as yy1, yy2, yy3, and yy4 inFIG. 17, the video stream is divided into pictures as I pictures, Bpictures, and P pictures each of which is a video presentation unit, andthe pictures are stored in a payload of each of the PES packets. Each ofthe PES packets has a PES header, and the PES header stores aPresentation Time-Stamp (PTS) indicating a display time of the picture,and a Decoding Time-Stamp (DTS) indicating a decoding time of thepicture.

FIG. 18 illustrates a format of TS packets to be finally written on themultiplexed data. Each of the TS packets is a 188-byte fixed lengthpacket including a 4-byte TS header having information, such as a PIDfor identifying a stream and a 184-byte TS payload for storing data. ThePES packets are divided, and stored in the TS payloads, respectively.When a BD ROM is used, each of the TS packets is given a 4-byteTP_Extra_Header, thus resulting in 192-byte source packets. The sourcepackets are written on the multiplexed data. The TP_Extra_Header storesinformation such as an Arrival_Time_Stamp (ATS). The ATS shows atransfer start time at which each of the TS packets is to be transferredto a PID filter. The source packets are arranged in the multiplexed dataas shown at the bottom of FIG. 18. The numbers incrementing from thehead of the multiplexed data are called source packet numbers (SPNs).

Each of the TS packets included in the multiplexed data includes notonly streams of audio, video, subtitles and others, but also a ProgramAssociation Table (PAT), a Program Map Table (PMT), and a Program ClockReference (PCR). The PAT shows what a PID in a PMT used in themultiplexed data indicates, and a PID of the PAT itself is registered aszero. The PMT stores PIDs of the streams of video, audio, subtitles andothers included in the multiplexed data, and attribute information ofthe streams corresponding to the PIDs. The PMT also has variousdescriptors relating to the multiplexed data. The descriptors haveinformation such as copy control information showing whether copying ofthe multiplexed data is permitted or not. The PCR stores STC timeinformation corresponding to an ATS showing when the PCR packet istransferred to a decoder, in order to achieve synchronization between anArrival Time Clock (ATC) that is a time axis of ATSs, and an System TimeClock (STC) that is a time axis of PTSs and DTSs.

FIG. 19 illustrates the data structure of the PMT in detail. A PMTheader is disposed at the top of the PMT. The PMT header describes thelength of data included in the PMT and others. A plurality ofdescriptors relating to the multiplexed data is disposed after the PMTheader. Information such as the copy control information is described inthe descriptors. After the descriptors, a plurality of pieces of streaminformation relating to the streams included in the multiplexed data isdisposed. Each piece of stream information includes stream descriptorseach describing information, such as a stream type for identifying acompression codec of a stream, a stream PID, and stream attributeinformation (such as a frame rate or an aspect ratio). The streamdescriptors are equal in number to the number of streams in themultiplexed data.

When the multiplexed data is recorded on a recording medium and others,it is recorded together with multiplexed data information files.

Each of the multiplexed data information files is management informationof the multiplexed data as shown in FIG. 20. The multiplexed datainformation files are in one to one correspondence with the multiplexeddata, and each of the files includes multiplexed data information,stream attribute information, and an entry map.

As illustrated in FIG. 20, the multiplexed data information includes asystem rate, a reproduction start time, and a reproduction end time. Thesystem rate indicates the maximum transfer rate at which a system targetdecoder to be described later transfers the multiplexed data to a PIDfilter. The intervals of the ATSs included in the multiplexed data areset to not higher than a system rate. The reproduction start timeindicates a PTS in a video frame at the head of the multiplexed data. Aninterval of one frame is added to a PTS in a video frame at the end ofthe multiplexed data, and the PTS is set to the reproduction end time.

As shown in FIG. 21, a piece of attribute information is registered inthe stream attribute information, for each PID of each stream includedin the multiplexed data. Each piece of attribute information hasdifferent information depending on whether the corresponding stream is avideo stream, an audio stream, a presentation graphics stream, or aninteractive graphics stream.

Each piece of video stream attribute information carries informationincluding what kind of compression codec is used for compressing thevideo stream, and the resolution, aspect ratio and frame rate of thepieces of picture data that is included in the video stream. Each pieceof audio stream attribute information carries information including whatkind of compression codec is used for compressing the audio stream, howmany channels are included in the audio stream, which language the audiostream supports, and how high the sampling frequency is. The videostream attribute information and the audio stream attribute informationare used for initialization of a decoder before the player plays backthe information.

In the present embodiment, the multiplexed data to be used is of astream type included in the PMT. Furthermore, when the multiplexed datais recorded on a recording medium, the video stream attributeinformation included in the multiplexed data information is used. Morespecifically, the moving picture coding method or the moving picturecoding apparatus described in each of embodiments includes a step or aunit for allocating unique information indicating video data generatedby the moving picture coding method or the moving picture codingapparatus in each of embodiments, to the stream type included in the PMTor the video stream attribute information. With the configuration, thevideo data generated by the moving picture coding method or the movingpicture coding apparatus described in each of embodiments can bedistinguished from video data that conforms to another standard.

Furthermore, FIG. 22 illustrates steps of the moving picture decodingmethod according to the present embodiment. In Step exS100, the streamtype included in the PMT or the video stream attribute informationincluded in the multiplexed data information is obtained from themultiplexed data. Next, in Step exS101, it is determined whether or notthe stream type or the video stream attribute information indicates thatthe multiplexed data is generated by the moving picture coding method orthe moving picture coding apparatus in each of embodiments. When it isdetermined that the stream type or the video stream attributeinformation indicates that the multiplexed data is generated by themoving picture coding method or the moving picture coding apparatus ineach of embodiments, in Step exS102, decoding is performed by the movingpicture decoding method in each of embodiments. Furthermore, when thestream type or the video stream attribute information indicatesconformance to the conventional standards, such as MPEG-2, MPEG-4 AVC,and VC-1, in Step exS103, decoding is performed by a moving picturedecoding method in conformity with the conventional standards.

As such, allocating a new unique value to the stream type or the videostream attribute information enables determination whether or not themoving picture decoding method or the moving picture decoding apparatusthat is described in each of embodiments can perform decoding. Even whenmultiplexed data that conforms to a different standard is input, anappropriate decoding method or apparatus can be selected. Thus, itbecomes possible to decode information without any error. Furthermore,the moving picture coding method or apparatus, or the moving picturedecoding method or apparatus in the present embodiment can be used inthe devices and systems described above.

Embodiment 5

Each of the moving picture coding method, the moving picture codingapparatus, the moving picture decoding method, and the moving picturedecoding apparatus in each of embodiments is typically achieved in theform of an integrated circuit or a Large Scale Integrated (LSI) circuit.As an example of the LSI, FIG. 23 illustrates a configuration of the LSIex500 that is made into one chip. The LSI ex500 includes elements ex501,ex502, ex503, ex504, ex505, ex506, ex507, ex508, and ex509 to bedescribed below, and the elements are connected to each other through abus ex510. The power supply circuit unit ex505 is activated by supplyingeach of the elements with power when the power supply circuit unit ex505is turned on.

For example, when coding is performed, the LSI ex500 receives an AVsignal from a microphone ex117, a camera ex113, and others through an AVIO ex509 under control of a control unit ex501 including a CPU ex502, amemory controller ex503, a stream controller ex504, and a drivingfrequency control unit ex512. The received AV signal is temporarilystored in an external memory ex511, such as an SDRAM. Under control ofthe control unit ex501, the stored data is segmented into data portionsaccording to the processing amount and speed to be transmitted to asignal processing unit ex507. Then, the signal processing unit ex507codes an audio signal and/or a video signal. Here, the coding of thevideo signal is the coding described in each of embodiments.Furthermore, the signal processing unit ex507 sometimes multiplexes thecoded audio data and the coded video data, and a stream IO ex506provides the multiplexed data outside. The provided multiplexed data istransmitted to the base station ex107, or written on the recordingmedium ex215. When data sets are multiplexed, the data should betemporarily stored in the buffer ex508 so that the data sets aresynchronized with each other.

Although the memory ex511 is an element outside the LSI ex500, it may beincluded in the LSI ex500. The buffer ex508 is not limited to onebuffer, but may be composed of buffers. Furthermore, the LSI ex500 maybe made into one chip or a plurality of chips.

Furthermore, although the control unit ex501 includes the CPU ex502, thememory controller ex503, the stream controller ex504, the drivingfrequency control unit ex512, the configuration of the control unitex501 is not limited to such. For example, the signal processing unitex507 may further include a CPU. Inclusion of another CPU in the signalprocessing unit ex507 can improve the processing speed. Furthermore, asanother example, the CPU ex502 may serve as or be a part of the signalprocessing unit ex507, and, for example, may include an audio signalprocessing unit. In such a case, the control unit ex501 includes thesignal processing unit ex507 or the CPU ex502 including a part of thesignal processing unit ex507.

The name used here is LSI, but it may also be called IC, system LSI,super LSI, or ultra LSI depending on the degree of integration.

Moreover, ways to achieve integration are not limited to the LSI, and aspecial circuit or a general purpose processor and so forth can alsoachieve the integration. Field Programmable Gate Array (FPGA) that canbe programmed after manufacturing LSIs or a reconfigurable processorthat allows re-configuration of the connection or configuration of anLSI can be used for the same purpose.

In the future, with advancement in semiconductor technology, a brand-newtechnology may replace LSI. The functional blocks can be integratedusing such a technology. The possibility is that the present disclosureis applied to biotechnology.

Embodiment 6

When video data generated in the moving picture coding method or by themoving picture coding apparatus described in each of embodiments isdecoded, compared to when video data that conforms to a conventionalstandard, such as MPEG-2, MPEG-4 AVC, and VC-1 is decoded, theprocessing amount probably increases. Thus, the LSI ex500 needs to beset to a driving frequency higher than that of the CPU ex502 to be usedwhen video data in conformity with the conventional standard is decoded.However, when the driving frequency is set higher, there is a problemthat the power consumption increases.

In order to solve the problem, the moving picture decoding apparatus,such as the television ex300 and the LSI ex500 is configured todetermine to which standard the video data conforms, and switch betweenthe driving frequencies according to the determined standard. FIG. 24illustrates a configuration ex800 in the present embodiment. A drivingfrequency switching unit ex803 sets a driving frequency to a higherdriving frequency when video data is generated by the moving picturecoding method or the moving picture coding apparatus described in eachof embodiments. Then, the driving frequency switching unit ex803instructs a decoding processing unit ex801 that executes the movingpicture decoding method described in each of embodiments to decode thevideo data. When the video data conforms to the conventional standard,the driving frequency switching unit ex803 sets a driving frequency to alower driving frequency than that of the video data generated by themoving picture coding method or the moving picture coding apparatusdescribed in each of embodiments. Then, the driving frequency switchingunit ex803 instructs the decoding processing unit ex802 that conforms tothe conventional standard to decode the video data.

More specifically, the driving frequency switching unit ex803 includesthe CPU ex502 and the driving frequency control unit ex512 in FIG. 23.Here, each of the decoding processing unit ex801 that executes themoving picture decoding method described in each of embodiments and thedecoding processing unit ex802 that conforms to the conventionalstandard corresponds to the signal processing unit ex507 in FIG. 23. TheCPU ex502 determines to which standard the video data conforms. Then,the driving frequency control unit ex512 determines a driving frequencybased on a signal from the CPU ex502. Furthermore, the signal processingunit ex507 decodes the video data based on the signal from the CPUex502. For example, the identification information described inEmbodiment 4 is probably used for identifying the video data. Theidentification information is not limited to the one described inEmbodiment B but may be any information as long as the informationindicates to which standard the video data conforms. For example, whenwhich standard video data conforms to can be determined based on anexternal signal for determining that the video data is used for atelevision or a disk, etc., the determination may be made based on suchan external signal. Furthermore, the CPU ex502 selects a drivingfrequency based on, for example, a look-up table in which the standardsof the video data are associated with the driving frequencies as shownin FIG. 26. The driving frequency can be selected by storing the look-uptable in the buffer ex508 and in an internal memory of an LSI, and withreference to the look-up table by the CPU ex502.

FIG. 25 illustrates steps for executing a method in the presentembodiment. First, in Step exS200, the signal processing unit ex507obtains identification information from the multiplexed data. Next, inStep exS201, the CPU ex502 determines whether or not the video data isgenerated by the coding method and the coding apparatus described ineach of embodiments, based on the identification information. When thevideo data is generated by the moving picture coding method and themoving picture coding apparatus described in each of embodiments, inStep exS202, the CPU ex502 transmits a signal for setting the drivingfrequency to a higher driving frequency to the driving frequency controlunit ex512. Then, the driving frequency control unit ex512 sets thedriving frequency to the higher driving frequency. On the other hand,when the identification information indicates that the video dataconforms to the conventional standard, such as MPEG-2, MPEG-4 AVC, andVC-1, in Step exS203, the CPU ex502 transmits a signal for setting thedriving frequency to a lower driving frequency to the driving frequencycontrol unit ex512. Then, the driving frequency control unit ex512 setsthe driving frequency to the lower driving frequency than that in thecase where the video data is generated by the moving picture codingmethod and the moving picture coding apparatus described in each ofembodiment.

Furthermore, along with the switching of the driving frequencies, thepower conservation effect can be improved by changing the voltage to beapplied to the LSI ex500 or an apparatus including the LSI ex500. Forexample, when the driving frequency is set lower, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set to a voltage lower than that in the case where the drivingfrequency is set higher.

Furthermore, when the processing amount for decoding is larger, thedriving frequency may be set higher, and when the processing amount fordecoding is smaller, the driving frequency may be set lower as themethod for setting the driving frequency. Thus, the setting method isnot limited to the ones described above. For example, when theprocessing amount for decoding video data in conformity with MPEG-4 AVCis larger than the processing amount for decoding video data generatedby the moving picture coding method and the moving picture codingapparatus described in each of embodiments, the driving frequency isprobably set in reverse order to the setting described above.

Furthermore, the method for setting the driving frequency is not limitedto the method for setting the driving frequency lower. For example, whenthe identification information indicates that the video data isgenerated by the moving picture coding method and the moving picturecoding apparatus described in each of embodiments, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set higher. When the identification information indicates thatthe video data conforms to the conventional standard, such as MPEG-2,MPEG-4 AVC, and VC-1, the voltage to be applied to the LSI ex500 or theapparatus including the LSI ex500 is probably set lower. As anotherexample, when the identification information indicates that the videodata is generated by the moving picture coding method and the movingpicture coding apparatus described in each of embodiments, the drivingof the CPU ex502 does not probably have to be suspended. When theidentification information indicates that the video data conforms to theconventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1, the drivingof the CPU ex502 is probably suspended at a given time because the CPUex502 has extra processing capacity. Even when the identificationinformation indicates that the video data is generated by the movingpicture coding method and the moving picture coding apparatus describedin each of embodiments, in the case where the CPU ex502 has extraprocessing capacity, the driving of the CPU ex502 is probably suspendedat a given time. In such a case, the suspending time is probably setshorter than that in the case where when the identification informationindicates that the video data conforms to the conventional standard,such as MPEG-2, MPEG-4 AVC, and VC-1.

Accordingly, the power conservation effect can be improved by switchingbetween the driving frequencies in accordance with the standard to whichthe video data conforms. Furthermore, when the LSI ex500 or theapparatus including the LSI ex500 is driven using a battery, the batterylife can be extended with the power conservation effect.

Embodiment 7

There are cases where a plurality of video data that conforms todifferent standards, is provided to the devices and systems, such as atelevision and a cellular phone. In order to enable decoding theplurality of video data that conforms to the different standards, thesignal processing unit ex507 of the LSI ex500 needs to conform to thedifferent standards. However, the problems of increase in the scale ofthe circuit of the LSI ex500 and increase in the cost arise with theindividual use of the signal processing units ex507 that conform to therespective standards.

In order to solve the problem, what is conceived is a configuration inwhich the decoding processing unit for implementing the moving picturedecoding method described in each of embodiments and the decodingprocessing unit that conforms to the conventional standard, such asMPEG-2, MPEG-4 AVC, and VC-1 are partly shared. Ex900 in FIG. 27A showsan example of the configuration. For example, the moving picturedecoding method described in each of embodiments and the moving picturedecoding method that conforms to MPEG-4 AVC have, partly in common, thedetails of processing, such as entropy coding, inverse quantization,deblocking filtering, and motion compensated prediction. The details ofprocessing to be shared probably include use of a decoding processingunit ex902 that conforms to MPEG-4 AVC. In contrast, a dedicateddecoding processing unit ex901 is probably used for other processingunique to an aspect of the present disclosure. Since the aspect of thepresent disclosure is characterized by inverse quantization inparticular, for example, the dedicated decoding processing unit ex901 isused for inverse quantization. Otherwise, the decoding processing unitis probably shared for one of the entropy decoding, deblockingfiltering, and motion compensation, or all of the processing. Thedecoding processing unit for implementing the moving picture decodingmethod described in each of embodiments may be shared for the processingto be shared, and a dedicated decoding processing unit may be used forprocessing unique to that of MPEG-4 AVC.

Furthermore, ex1000 in FIG. 27B shows another example in that processingis partly shared. This example uses a configuration including adedicated decoding processing unit ex1001 that supports the processingunique to an aspect of the present disclosure, a dedicated decodingprocessing unit ex1002 that supports the processing unique to anotherconventional standard, and a decoding processing unit ex1003 thatsupports processing to be shared between the moving picture decodingmethod according to the aspect of the present disclosure and theconventional moving picture decoding method. Here, the dedicateddecoding processing units ex1001 and ex1002 are not necessarilyspecialized for the processing according to the aspect of the presentdisclosure and the processing of the conventional standard,respectively, and may be the ones capable of implementing generalprocessing. Furthermore, the configuration of the present embodiment canbe implemented by the LSI ex500.

As such, reducing the scale of the circuit of an LSI and reducing thecost are possible by sharing the decoding processing unit for theprocessing to be shared between the moving picture decoding methodaccording to the aspect of the present disclosure and the moving picturedecoding method in conformity with the conventional standard.

Each of the structural elements in each of the above-describedembodiments may be configured in the form of an exclusive hardwareproduct, or may be realized by executing a software program suitable forthe structural element. Each of the structural elements may be realizedby means of a program executing unit, such as a CPU and a processor,reading and executing the software program recorded on a recordingmedium such as a hard disk or a semiconductor memory. Here, the softwareprogram for realizing the image decoding apparatus according to each ofthe embodiments is a program described below.

The herein disclosed subject matter is to be considered descriptive andillustrative only, and the appended Claims are of a scope intended tocover and encompass not only the particular embodiments disclosed, butalso equivalent structures, methods, and/or uses.

INDUSTRIAL APPLICABILITY

The moving picture coding method and moving picture decoding methodaccording to one or more exemplary embodiments disclosed herein areapplicable to various applications such as information displayapparatuses and image capturing apparatuses which support highresolution. Examples of such apparatuses include a television set, adigital video recorder, a car navigation system, a cellular phone, adigital camera, and a digital video camera.

The invention claimed is:
 1. A decoding circuit comprising: processingcircuitry; and non-transitory storage coupled to the processingcircuitry, wherein the processing circuitry is configured to perform thefollowing: obtaining, from a coded signal, a luminance CBF flagindicating whether or not a quantized coefficient is included in atransform unit that is included in a coding unit of the image; selectinga first probability table or a second probability table so that (i) thefirst probability table is selected when the size of the coding unit isidentical to the size of the transform unit and (ii) the secondprobability table is selected when the size of the coding unit is notidentical to the size of the transform unit regardless of the size ofthe transform unit; performing arithmetic decoding on the luminance CBFflag using the selected one of the first probability table and thesecond probability table; and decoding a picture signal for the codingunit using the quantized coefficient of the transform unit when theluminance CBF flag indicates that the quantized coefficients is includedin the transform unit, wherein when the size of the transform unit is afirst size which is smaller than the size of the coding unit, theselecting selects the second probability table, wherein when the size ofthe transform unit is a second size which is smaller than the firstsize, the selecting selects the second probability table withoutdepending on any surrounding blocks.
 2. An encoding circuit comprising:processing circuitry; and non-transitory storage coupled to theprocessing circuitry, wherein the processing circuitry is configured toperform the following: obtaining a luminance CBF flag indicating whetheror not a quantized coefficient is included in a transform unit that isincluded in a coding unit of the image; selecting a first probabilitytable or a second probability table so that (i) the first probabilitytable is selected when the size of the coding unit is identical to thesize of the transform unit and (ii) the second probability table isselected when the size of the coding unit is not identical to the sizeof the transform unit regardless of the size of the transform unit;performing arithmetic encoding on the luminance CBF flag using theselected one of the first probability table and the second probabilitytable; and encoding a picture signal for the coding unit using thequantized coefficient of the transform unit when the luminance CBF flagindicates that the quantized coefficients is included in the transformunit, wherein when the size of the transform unit is a first size whichis smaller than the size of the coding unit, the selecting selects thesecond probability table, wherein when the size of the transform unit isa second size which is smaller than the first size, the selectingselects the second probability table without depending on anysurrounding blocks.